FACILITY FOR STAGE CEMENTING OF WELL Russian patent published in 2004 - IPC

FIELD: oil and gas industry, two-stage cementing of casing strings in oil and gas wells. SUBSTANCE: facility has body with side holes, enclosure, valve unit, upper and lower driving plugs. Body and enclosure form space around their entire edges. Shut-off element of valve unit comes in the of form of bushing interconnected telescopically and linked to body. Bushings lean with upper butts against springs and springs rest against rest. Rest is made fast to body. Facility is fitted with additional valve placed between enclosure and body and with mobile bushing installed inside body. Valve and bushing are located above side holes in body and are connected to it with the use of shear elements. EFFECT: high carrying capacity of facility in process of injection of second stage slurry, facility shows high functional reliability and degree of sealing. 3 cl, 1 dwg